Method for feeding an operating motor of a rolling shutter and a device for a driven rolling shutter

Abstract

The inventive method makes it possible to feed an alternating current electric motor used for operating a rolling shutter in a building by means of a gear whose performance substantially varies when a movable element drives or is driven by the rolling shutter. The electric motor is supplied, in certain phases, at a reduced tension, wherein the motor slipping measuring a relative speed deviation with respect to a zero running torque speed remains less the motor slipping when the rotor thereof ruts at a nominal speed at least if the rolling shutter does not meet obstacles. The drive for the rolling shutter for carrying out said method is also disclosed.

1. A method for powering an alternating current induction motor (MOT) used to lower or raise a movable element (LD) for closure, privacy, sun protection or screening in a building, by means of a reduction gear (GER) having a substantially different efficiency depending on whether the movable element drives or is driven by the motor, the movable element (LD) comprising a bottom end whose movements between an extreme bottom position and an extreme top position are caused by rotary movements of the motor (MOT), the electric motor being powered, in some periods, at reduced voltage, wherein the absolute value of slip of the motor, measuring the relative difference of speed relative to the speed at zero torque, remains less than the absolute value of slip of the motor when its rotor rotates at rated speed, at least so long as the movable closure element does not encounter an obstacle, the rated speed being defined as the speed of the rotor of the motor when the latter is powered at rated voltage and when the movable element exerts a maximum load. 
     
     
       2. The powering method as claimed in  claim 1 , wherein the motor (MOT) is powered at reduced voltage to cause the movements for moving the bottom end of the movable element toward the extreme bottom position. 
     
     
       3. The powering method as claimed in  claim 1  wherein the motor (MOT) is powered at rated voltage to cause the movements for moving the bottom end of the movable element (LD) toward the extreme top position so long as a particular condition is not met, and in that the motor (MOT) is powered at reduced voltage to cause the movements for moving the bottom end of the movable element (LD) toward the extreme top position when the particular condition is met. 
     
     
       4. The powering method as claimed in  claim 3 , wherein the particular condition is the motor torque passing below a threshold. 
     
     
       5. The powering method as claimed in  claim 3 , wherein the particular condition is predetermined by fixing a relative duration relative to the total duration of operation between the extreme positions. 
     
     
       6. The powering method as claimed in  claim 3 , wherein the particular condition is determined in a learning phase. 
     
     
       7. The powering method as claimed in  claim 6 , wherein the particular condition is defined as a particular value calculated as a fraction of the content of a counter corresponding to the total travel, using a predetermined coefficient. 
     
     
       8. The powering method as claimed in  claim 6 , wherein the particular condition is determined by a particular action on control means when the movable element passes a position in which only a small fraction of the total travel remains to be traveled. 
     
     
       9. The powering method as claimed in  claim 7 , wherein a value of a position counter is stored in a memory when the motor torque passes the threshold during a movement between the extreme end-of-travel positions. 
     
     
       10. The powering method as claimed in  claim 1 , wherein the particular condition is the bottom end of the element reaching a position defined by a period of activation of the motor from one of the extreme positions of this end. 
     
     
       11. The powering method as claimed in  claim 1 , wherein the motor (MOT) is supplied through a triac (TRC) whose state is controlled by a control device (SCU) generating electric pulses at a frequency that is double that of the supply voltage, these pulses being generated substantially at the moments when the supply voltage is zero, to supply the motor at rated voltage, and substantially after the moments when the supply voltage is zero, to supply the motor at reduced voltage. 
     
     
       12. The powering method as claimed in  claim 11 , wherein, to supply the motor at reduced voltage, the electric control pulses generated by the control device (SCU) have a delay relative to the moments when the supply voltage is zero that differs depending on whether the supply voltage value is positive or negative. 
     
     
       13. The powering method as claimed in  claim 1 , wherein the RMS value of the reduced voltage is less than 75% of the RMS value of the rated voltage. 
     
     
       14. An actuator (ACT) comprising an alternating current electric motor (MOT) used to operate a movable element (LD) for closure, privacy, sun protection or screening in a building, by means of a reduction gear (GER) having a substantially different efficiency depending on whether the movable element drives or is driven by the motor, the motor being powered by a source of alternating voltage through a triac (TRC), which actuator comprises hardware means (TCU, CPU, SCU) and software means for implementing the method according to  claim 1 . 
     
     
       15. The actuator as claimed in  claim 14 , wherein the alternating current electric motor (MOT) is single-phase, of the induction type with two windings (W 1 , W 2 ) and a permanent split capacitor (CM). 
     
     
       16. The actuator as claimed in  claim 14 , wherein the reduction gear (GER) has an efficiency greater than 70% when the movable element is driven by the motor and less than 60% when the movable element drives the motor. 
     
     
       17. The actuator as claimed in  claim 14 , wherein the reduction gear (GER) has an efficiency when the movable element is driven by the motor at least 15% greater than the efficiency when the movable element drives the motor. 
     
     
       18. An installation comprising an actuator (ACT) as claimed in  claim 14  operating a movable element (LD), wherein the absolute value of the maximum torque exerted by the movable element on the motor when the latter drives the movable element is at least twice as much as the absolute value of the maximum torque exerted by the movable element on the motor when the latter is driven by the movable element.